EXAMINATION OF TEXTILE FIBRES. 91 



scales are large and project prominently from the fibre, so 

 that they interlock with each other and materially in- 

 crease the compactness of the tissue. Some thirty-two 

 varieties of sheep (bebnging to the genus Ovis) furnish 

 the wool of commerce besides the llama, or alpaca goat, 

 the Thibet or Cashmere goat, and the Angora goat, from 



Fig. 37. — ^Wool-fibres. (After Hassack.) 200 diameters. 



which mohair is derived'. The length of wool varies 

 from 2 to 20 cm., and its diameter from 10 to 100 fx; the 

 larger fibres are combed and spun into worsted yarns, 

 the shorter are carded and spun into woolen yarns. 



The separation of wool from vegetable fibres under 

 the lens is sufficiently simple; but the application of the' 

 microscope only begins here. The hair from various" 

 animals should be carefully studied; comparison of 



